


Thus Saith the Lord

by Sin_Cognito



Category: Undertale (Video Game)
Genre: Alternate Universe - Swapfell, Fontcest, M/M, My First Fanfic, My First Smut, Sex Toys, Sibling Incest, Smut, Swapfell AU, Swapfell Sans, or rather
Language: English
Status: Completed
Published: 2017-07-13
Updated: 2017-07-13
Packaged: 2018-12-01 16:20:19
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,563
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11490099
Author URL: https://archiveofourown.org/users/Sin_Cognito/pseuds/Sin_Cognito
Summary: Entry for the fontcest fanfic contest by aryisgoingaway and nagisaheichou on tumblr !Sans and Papyrus play a new game.





	Thus Saith the Lord

What game would they play today ?

 

Toying with his baby blue bandana, Sans was pacing impatiently in Papyrus’ former bedroom, which they had transformed into a playroom a long time ago. He had announced during dinner that they would play something new tonight, but he had yet to decide what kind of game. He still had gone upstairs to prep himself and the playground, and Papyrus was taking advantage of the respite to take a nap downstairs. Sans’ new games usually took their toll on both skeletons and Papyrus had learnt to rest if he wanted to be able to keep up with his brother. Or rather, he had been taught.

Sans’ icy blue gaze set upon the collection of dildos and sex toys the two had gathered through the years. He had tested every single one of them himself, before introducing them to Papyrus. While he admittedly would always prefer his brother’s magic inside him, some of the dildos had left their mark on him… The toys were only used for Papyrus’ pleasure these days, but Sans was pretty sure his brother wouldn’t mind sharing. Especially with him.

 

Okay. He had decided on the game.

 

Calling for Papyrus to come upstairs, the tall skeleton was, to Sans’ delight, in the room within seconds. He must’ve been as excited as him.

“Remove your shirt Papyrus. I want to be able to see your soul.”

Papyrus obeyed but couldn’t help being a bit intrigued. Not by Sans wanting to see his soul, no, that would be absurd. He BELONGED to Sans, Body, Magic and Soul. But Sans had called him “Papyrus”. Hadn’t they already started the game ? Sans easily noticed the silent trouble.

“Do you remember how when we were little, we used to play "Simon Says” ? Well I want to play it right now. So you’ll have to obey every command that starts by “Sansy Says”. If you fail to comply or perform an action that “Sansy didn’t Say”, you’ll have to face a punishment. Am I understood ?“

Sans could see Papyrus carefully choosing his next words. It was natural though, as it was the first time they would PLAY without being Lord and servant. And papyrus wasn’t used to that.

"Yes” Papyrus answered.

Sans felt relieved at that. He instantly knew Papyrus had agreed to the silent order not to obey his Lord. Tonight, it was all about Sansy.

“Sansy Says to remove Sansy’s clothes.”

The first order came down hard. Sans was already pushing his brother’s limits. Usually, Papyrus would never, NEVER be allowed to strip his Lord himself. Not with his filthy, unworthy, bare hands. And also, the little Lord quite enjoyed His servant’s reaction to Him undressing Himself. But he would never let the other know that.

Papyrus came closer to Sans and removed his shirt with barely trembling hands. The Lord’s own hands twitched in annoyance of His slave daring to touch His garment, but Sans was also so very proud of his brother following the rules he had established. The boots and the pants were soon to follow the shirt on the floor and Sans stood naked in the middle of the room. Papyrus daring hands lifted to Sans’ nape of the neck and began untying the bandana. The little skeleton frowned and gripped the other’s wrists before he could remove the piece of fabric completely from his shoulders.

“Don’t” He warned.

Remains of their lost childhood, he couldn’t even dream of not having his blue bandana draped around him. Even Papyrus was very rarely allowed to touch it.  
To his surprise, his brother gripped both his tiny hands into his bigger one and yanked the fabric with his free hand.

 

“What does Sansy Say now ?”

 

The guts.

 

Despite being visibly uspset with the rough treatment given to his most valued garment, Sans felt his grin stretch further. Stars, he already loved this game.

“It’s Christmas. Sansy Says to take the bullet vibrators and decorate.”

Something shifted in Papyrus’ gaze. A primal and raw desire replaced the usual lazy and submissive look on the other’s face. Was it because of the nature of the order, or because he had chosen specifically one of Papyrus’ absolute favorite sex toy ? Sans didn’t know, and honestly didn’t care.

The tall skeleton immediately got down to work, litteraly, kneeling in front of Sans and taking his time uncoiling the bullets’ otherwise disentangled cable. Slowly, oh so slowly, he weaved the strings around Sans’ ribcage, securing the ends to the bones so that only the small skeleton would fall apart. He was about to set the vibrators on low speed when Sans spoke up.

“Did Sansy Say to turn it on ?” He said with a grin.

Papyrus’ reaction was priceless. His face morphed into guilty remorse while his soul flushed brighter, a crystal clear token of his excitement at the thought of a punishment. Trying no to break from his role and take his brother right there and then, Sans cleared his throat and extended his hands towards the other’s ribcage.

“Sansy Says to tie his arms.”

And tied were his arms. Knowing by heart the sentation of rope against bones, Papyrus chose the softest one they had, so as not to leave a single mark on Sans’ wrists. What if he got hurt and couldn’t inflict the promised punishment to the disobedient monster ? That would be a shame.

After tying the rope above Sans’ head, Papyrus stepped back to await the next order.

“Sansy Says to get the spreader bar.’

Now he knew it would become difficult. Papyrus was much taller than him, and they had a collection of spreader bars adapted to someone his size. Sans’ legs were shorter, and the last time he had tried one of their spreader bar hadn’t been very satisfying. Quite painful, actually, and not even in a pleasant way. But he needed it for what he intended on making Papyrus do next. After another thoroughly followed order, Sans found himself perfectly tied from head to toe, unable to move more than a few millimeters.

The little skeleton was honestly impressed with Papyrus’ work, knowing his tall borther was more used to be the one being tied. He surely knew how to tie knots.

Now that everything was ready, the real fun could begin.

"Sansy Says to turn the vibrators on sl… medium.”

Visibly not perturbed by Sans’ little slip-up, Papyrus pressed the vibrators button to the desired speed and watch with awe the short skeleton jerk against the bonds, a tiny squeak finding its way out of him.

Sans hadn’t been surprised, per say, he was the one who gave the order after all, but he hadn’t fully realised how turned on he had been up to now. The low hum of the vibrators was sending soft pulses of electric shock to his bones. He hadn’t paid attention to where Papyrus had attached the bullets, but now stars did he notice how the other knew all of his weak points. The ones on his lower ribs were particularly deliciously horrible.

It took very little time for the magic that had pooled in his core to take shape, morphing into a baby blue pussy, already wet and ready to be fucked. But not just yet, he wanted to have a little more fun. Though it was hard not to succumb to his desires as he opened the eyes he hadn’t noticed he had closed, and took in the sight of Papyrus, soul glowing brightly in his chest and bulge in his pants.

“Now… haa… Sansy Says to take your f-favorite dildo and… haaan.”

Well, at least Papyrus had gotten half of the message. He went to the drawer where their dildos were stored and took his time in choosing the perfect one. Honnestly, there wasn’t a single one in the drawer he didn’t absolutely adored, as each one was related to blissful memories. But that didn’t mean he would choose just any dildo. Sans deserved the very best. Speaking of the skeleton, Papyrus turned his head to see him shivering in his bonds, the sight oh so priceless of his brother drooling, moaning and whispering his name. He perfectly knew he wouldn’t come just because of some vibrator bullets tied to his ribcage. He was the resistant one after all.

Papyrus drew closer to the quivering skeleton, dildo in hand and smirk on his face. Putting a finger under the other’s chin, he lifted up Sans’ adorably flushed face and opened his mouth, only to turn away at the last moment and he licked the dildo, sliding his orange tongue along the shaft. He sucked hard, efficiently slicking the toy with his magic. All while looking at Sans directly in the eye socket.

“What are you doing ? Sansy didn’t Say to lubricate the dildo, only to go fetch it.” Sans said sharply. His idea had been to order Papyrus to make HIM suck the toy. Now that his plan to arouse the other were off the table, he had to-  
“Sansy didn’t Say not to either.”

 

The insolent little shit.

 

The tiny Lord hated when His slave got arrogant, but Sans absolutely loved a cocky Papyrus. The rare times he had allowed this kind of behavior into their play, he had been more than pleased with the results, but he still had to be careful or papyrus might get used to it.

“Then Sansy Says now that it’s ready, make use of it.”

He had barely said the order that the dildo was deliciously thrust deep into his blue pussy. Thankfully it had been wet enough (for quite a while even) not to hurt, and Sans couldn’t help the desperate cry of pleasure escaping him. Papyrus allowed him to catch his breath before gently pulling the dildo out and pushing it inside once more. He set a languid pace, far too slow in Sans’ opinion, but still satisfying enough to leave him breathless.

“Yes… Fu-fuck, Pap… faster… Come on… haa…”

Papyrus suddenly stilled his hand completely and moved a good 3 feet away from Sans. Completely taken aback from the out of the blue action, the little skeleton couldn’t help a groan at the loss of friction, as slow as it was.  
“N-no ! Come back !”

He immediately regretted his words as they would only incite papyrus to do just the opposite, for it wasn’t what Sansy had Said. It was clear the tall skeleton found it hard too not to obey his Master in this moment of vulnerability, but he managed to stand still, arms behind his back. And that was when Sans realised the dildo was still inside him. But what good would it do if he couldn’t move it ? His hands were still utterly bound and he feared moving his hips would only result in the sex toy dropping from his-

 

**vrrrrrrrrrrrrrrrr**

 

Sans’ head jerked back, his tongue lolled out of his mouth and he shut his eye sockets so hard he could swear his skull would crack in half.

Papyrus’ gaze burned into Sans. There, hidden in the palm of his bony hand, lay the dildo’s remote, the power button pressed to the highest speed. The tall skeleton couldn’t even begin to imagine how good it would feel to fuck Sans right now. The little skeleton was a complete mess, magic drooling from his perfect mouth, his ivory bones flushing his signature baby blue.

“Haaa, n-nn… Ple-… ah ! AH !”

He needed to cum, he needed it so badly. He wanted to ask, to BEG papyrus to let him, but Sans knew he would never be able to word his need, not in the state he was in. That was so typical of him ! HE had suggested the game, for fuck’s sake ! And now, he wasn’t remotely able to put an end to it, but, stars, did he need to cum. Please !

Sweat dripping from his skull, drool on his face and erotic juices leaking from his pussy, he pleaded with heart-shaped eyelights to his brother.  
“Papy… Please…” he whined.

 

_Game Over_

 

“Papy Says to cum.”

 

For a blissful, violent but oh so sweet second, Sans forgot everything. He could only feel the euphoric extasy of his orgasm rippling through his bones. He came hard in a silent cry. He felt his frame convulse and his bones rattle.

“Haa…”

He kept his eyes closed as he slowly came down from his high and relaxed in papyrus’ hold. He didn’t need to open his eyes to know he was safely nestled into his mate’s loving embrace. He had felt it.

Papyrus had soul fucked him.

They didn’t engage into soul fucking very often. It was even extremely rare. Sans could still feel the unmistakable magic of his brother course through him, leaving him sighing in pure bliss, even moments after his orgasm.

He distantly felt beloved arms tightening around him and then he was lifted up, his tired head resting softly in the crook of his mate’s neck. He then was gently laid on a fluffy bed. The silk sheets pressed heavenly sweet kisses all over his sleepy body. Or was it his lover kissing him ? He didn’t know anymore. His mind was filled with cotton. He just wanted to sleep and never wake up again. But he forced himself to open his eye sockets. He wanted to engrave papyrus’ image into his soul, to cherish forever, as he did every single time they made love.  
His eyelights blurred into hazy hearts at the sight of papyrus’ warm and caring gaze.

 

“I love you.”

 

Sans was already out as Papyrus bent down and clanked their teeth together into a tender kiss.

~

He wasn’t very sure when he had woken up, but he had been caressing Papyrus’ cheek for a good 20 minutes before speaking up.

“Papyrus. I love you.”

“I love you too, Sans.”

His name sounded so foreign in his brother’s mouth. He didn’t get to be called anything other than “m'Lord” often. But he prefered it this way. They both had been wearing the masks of Master and pet for so long now that it was uncomfortable for them not to be in their respective role. But it also meant that the moments when they were “Sans” and “Papyrus”, the two skeleton brothers from Snowdin, were the most precious and special, jealously kept safe behind their “official” way of life.

Right now, Sans simply loved papyrus, and Papyrus loved Sans back. It brought a genuine smile to the petite skeleton’s usually frowning face.

“How did you notice I wouldn’t be able to give the last order ?”

“I looked at you.”

Surprised by the simple answer, Sans made to sit up on his elbows, but a dull pain warned him not to attempt something so physical right away. Ooh. He wouldn’t be able to walk the next day, that was for sure.

“You looked at me ?” He merely repeated.

“I saw in your soul that you said the safe word. You just said it silently.” Papyrus explained. “It’s not because you don’t use words to tell me something that I won’t listen.”

Sans rebelled once again against is aching body and hugged papyrus tighter, if that was even possible. His gaze was lost into his lover’s one.

“Can you hear what I’m saying ?”

“Yes”

There was no need for hesitation.

 

_I love you._


End file.
